Avalanche Forecast

Issued: Nov 17th, 2017 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs and Storm Slabs.

tim haggarty, Parks Canada

Banff Yoho Kootenay.

With fresh slabs over a weak layer, avalanche activity can be expected this weekend. Skiers should take a cautious approach with steep or large slopes and climbers should consider their exposure to overhead avalanche terrain.

Summary

Weather Forecast

Sunday, models show up to 25 cm of snow to fall by Monday morning with temperatures sticking to the -5 to -10C range. Alpine winds will continue in the strong range through Sunday.

Snowpack Summary

Flurries continued today with moderate West winds to bring storm amounts to 15 to 25cm in the last 48 hours. The alpine snowpack ranges from 50-100 cm across the region with the main feature to watch in the snowpack being a layer of facets now buried 25 to 40 cm . Below 2700m these facets sit above a temperature crust that was buried on Halloween.

Avalanche Summary

Yesterday, forecasters kicked off a size 1.5, 30-40cm deep soft storm slab over facets today in a steeper alpine moraine feature.Â Similar avalanches were reported today on Mt Ogden. Our tour found more wind effect in Sunshine area today. Sunshine patrollers reported continued activity over the facets with windslabs building in the alpine.

Confidence

Intensity of incoming weather systems is uncertain on Sunday

Problems

Wind Slabs

Strong West winds were moving a great deal of snow today in the alpine. With more snow on the way Sunday and sustained winds, expect these slabs to continue to develop.

Use caution in lee areas. Recent wind loading has created wind slabs.Choose ice climbs that are not exposed to avalanches from above.

Aspects: North, North East, East, South East.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Storm Slabs

The snow that fell on Halloween became faceted by the early November cold snap. Soft slabs of snow now sit above this weak snow and have been reactive to skier traffic and small triggers such as sluffs out of rocky terrain.

Minimize exposure to steep, planar slopes.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Nov 18th, 2017 4:00PM